Browse Topic: Braking systems

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Global–Regional Energy Balance Climate Modeling Framework for Country-Level Temperature Projections Based on CO₂ Radiative Forcing2026-24-0021To be published on 09/21/2026
This study presents a computational framework for estimating country-level temperature projections based on global radiative forcing from CO₂ emissions. The methodology integrates a carbon-cycle accumulation module, a logarithmic radiative forcing formulation, and a dynamic one-box energy balance model (EBM) to simulate global mean temperature evolution. Atmospheric CO₂ concentration is computed from cumulative global emissions using an airborne fraction parameter. Radiative forcing is then determined using the established logarithmic relationship between concentration and forcing. The global temperature response is calculated dynamically by solving the transient energy balance equation, incorporating effective heat capacity and climate sensitivity parameters. To regionalize projections without relying on high-resolution General Circulation Models (GCMs), an empirical regional amplification factor is introduced. This coefficient is derived from historical regression between observed
Gutierrez, Marcos, Taco, Diana, Sampietro-Saquicela, Jose, Bermudez-Herrera, Leandro
Characterisation of Brake Wear PM2.5 and PN10 Emissions Across Pad/Disc Technologies, Vehicle Types and Braking Behaviours, Under Real World Conditions2026-24-0022To be published on 09/21/2026
This paper summarises targeted brake emissions investigations undertaken as part of the Department for Transport’s Non Exhaust Emissions programme. The work was carried out to improve understanding of particulate mass and particle number emissions from friction braking and to assess the influence of component selection, vehicle technology, operating conditions, and control measures on those emissions. Starting from a pre-developed brake enclosure and sampling system methodology, these were further refined to improve airflow management, reduce leakage, and minimise sampling artefacts. The updated system was integrated with a suite of particulate measurement instruments, including MPEC (hot and cold), APC10, DMS500, and eFilter, enabling simultaneous measurement of volatile and non volatile PN10 plus PM2.5. A matrix of nine brake pad formulations and two disc types was tested on a common C segment vehicle platform across chassis dyno and on road cycles, together with controlled braking
Andersson, Jon
Component Dynamics of a Motorcycle Brake Caliper: Analysis and Experimental Validation of Seal-Groove Mechanics and Controlled Rollback Design.2026-01-0823To be published on 09/14/2026
Pad - Rotor separation is critical to effective braking performance, pedal feel and NVH. In floating brake calipers, this separation is primarily governed by the seal and groove mechanics. Current studies primarily focus on the mechanics through empirical methods on single seal-groove systems for car calipers. However, a significant literature gap exists for motorcycle seal grooves and any system that utilizes a two seal-groove system with a primary pressure seal and a secondary dust seal. Since 75% of automobiles registered in India are motorcycles and Anti-lock braking becoming mandatory from 2026, designing a caliper with precise seal-groove mechanics becomes critical. This study proposes a theoretical framework by modeling the seals as a shear-beam and predicting the rollback using stick-slip hysteresis and resistive forces of the piston. Experimental validation was performed on three production motorcycle calipers, with the measured rollback and the piston push following the
Vaitheeswaran, Gyaneshwar, N, Manoj, M, Mahesh, Yogesh, Deepak, Rai, Ashutosh
Machine Learning Prediction of Wear of NAO Brake Pad Using Scaled-Down FMVSS 135 Testing2026-01-0808To be published on 09/14/2026
Brake pad lifespan significantly influences environmental pollution and public health due to non-exhaust particulate emissions. Global vehicle production reached approximately 7 billion units in 2025, with brake systems generating an estimated 50,000 to 100,000 metric tons of wear debris annually, underscoring the need for improved durability and material optimization. This study investigates the capability of a Fully Connected Neural Network (FCNN) to predict brake pad wear and support formulation optimization. Controlled experiments were performed using a simplified FMVSS 135 protocol on a Universal Mechanical Tester (UMT) to simulate realistic braking conditions. Wear loss was measured under varying normal loads, sliding velocities, and interface temperatures. An FCNN was selected for its ability to capture nonlinear interactions between operating conditions and tribological responses. Despite a limited but high-quality dataset, the application of data standardization
Katakam, Abhishek, Eslamiat, Hossein, Kancharla, Sai Krishna, Filip, Peter
Optimization of Hydraulic Disc Brake Caliper Parameters to Achieve Near Zero Residual Drag in Two-Wheeler Brake Systems2026-01-0820To be published on 09/14/2026
Residual drag in hydraulic disc brake systems is an inherent phenomenon caused by elastic deformation of piston seals, geometric tolerances, and frictional interaction between piston, seal, and brake pads. Even minimal unintended pad-to-disc contact after brake release can generate residual torque, leading to increased rolling resistance, temperature rise, accelerated pad wear, and reduced vehicle efficiency. With growing emphasis on performance optimization and energy efficiency in two-wheeler applications, minimizing brake drag without affecting braking response has become an important design objective. This paper presents the design, analysis, and experimental validation of a zero-drag floating brake caliper concept developed to reduce residual brake torque through optimization of piston seal characteristics and groove geometry. The study focuses on understanding piston rollback behavior as the primary mechanism governing pad clearance after pressure release. Analytical evaluation
Badade, Ashish Laxman
Architecting Safety-Critical Systems for AI-Enabled Software-Defined Vehicles: A Compute, Timing, and Isolation Framework with a Brake System Case Study2026-01-0811To be published on 09/14/2026
Software-defined vehicle (SDV) platforms are reshaping safety-critical system design by consolidating braking and other motion-control functions on centralized heterogeneous edge compute that also executes physical-AI workloads. This consolidation breaks traditional assumptions of fixed ECUs and simple timing envelopes, complicating assurance of determinism, isolation, and fail-operational behavior for ASIL-D brake functions. Building on a decentralized brake-by-wire (BbW) architecture with dual controllers, redundant low-voltage power grids, and smart electromechanical brake corner actuators, this paper proposes a systems-level framework for architecting safety-critical functions in AI-enabled SDVs along three dimensions: compute, timing, and isolation. The framework classifies conventional and AI-based functions and maps them to heterogeneous compute classes; defines architectural patterns that combine safety islands, power-domain redundancy, and hardware partitioning to support
srinivasaraghavan, soumyasudharsan
Influence of Scrub Radius on Steering Dynamics, Bearing Durability and Wheel-End Packaging in Heavy Commercial Vehicles2026-01-0831To be published on 09/14/2026
Front axle geometry is a critical determinant of vehicle performance in heavy commercial vehicles (HCVs), directly influencing steering feel, component life, and maintenance costs. This paper investigates the effects of increasing scrub radius—defined as the lateral distance between the tire contact patch center and the steering axis intersection with the ground—on steering dynamics, durability, and packaging. A larger kingpin offset generating a positive scrub radius improves steering leverage and reduces steering torque, particularly beneficial for power-assisted steering systems. However, its broader implications for wheel-end design require detailed evaluation. High-fidelity multi-body dynamics models, validated through instrumented vehicle testing, were employed to quantify these effects under diverse scenarios, including low-speed maneuvering, high-speed lane changes, and severe braking. Results indicate that a controlled increase in scrub radius (10–20 mm) reduces steering
Pandiyan, Mahendran, Saxena, Saurabh
Assessing brake wear particle emissions and performance characteristic of NAO-ceramic formulation for Euro 7 Compliance2026-01-0828To be published on 09/14/2026
EU7 regulation has focused on non-exhaust emission from brake and tire wear and has set the brake particle emission limits accordingly. The current PM10 limit is set at 7 mg/km for IC vehicles and 3 mg/km for EV (electric/battery vehicles) of M1, N1 category. Hence, the brake particle emissions test should be conducted according to the UN Global Technical Regulation No. 24 (GTR-24) procedure on the brake inertia dynamometer. Due to these new requirements; brake systems need to be homologated with regard to EU7 emissions limits. In this study, NAO-ceramic formulation is developed and tested for performance, wear, noise and brake emission on brake inertia dyno using the global standards such as SAE J2522 (AK-Master Performance), SAE J2707B (Block Wear Test), SAE J2521 (NVH) and, Emission Test (WLTP/GTR-24. The developed NAO-ceramic friction grade not only having better friction, wear and NVH properties, but also reduce the brake emissions substantially and meets the current PM10 limit
Kumar, Mukesh, Tomar, Bharat, Ali, Sharafat, Kalel, Navnath
Thermomechanical Fatigue Life Prediction of Lamellar Graphite Cast Iron Brake Disks Using Advanced Material Models and Elastic-Plastic Fracture Mechanics2026-01-0816To be published on 09/14/2026
A comprehensive thermomechanical fatigue (TMF) life prediction methodology is developed for cast iron brake disks. The approach employs transient temperature fields as thermal loads in a nonlinear structural finite-element analysis (FEA). To obtain reliable stress and strain histories for cast iron, a time- and temperature-dependent plasticity model is required that captures viscous effects, nonlinear kinematic hardening, and tension–compression asymmetry. For this purpose, a unified elasto-viscoplastic Chaboche constitutive model coupled with damage is developed and implemented as a user material subroutine (UMAT) in the general-purpose FEA software Abaqus by Dassault Systèmes. In addition, a mechanism-based short-crack TMF model is extended to three-dimensional stress states under transient non-proportional loading conditions for TMF life prediction. The material parameters of the constitutive and the damage models are identified for lamellar graphite cast iron using isothermal and
Lee, Heewook, Garcia, Arnoldo, Liu, Yi, Hazime, Radwan, Boughanmi, Heni, Kassir, Abdallah
Comparison of the Surfaces and Coefficients of Friction of Truck Brake Pads Tested on a Flywheel Test Bench and a Scaled Tester – A Case Study2026-01-0826To be published on 09/14/2026
Mechanical brakes have been used and studied in many areas of mechanical engineering and automotive technology for decades. However, the processes in the contact zone have not yet been described with sufficient accuracy. One reason for this is the inability to observe the contact zone during contact. Studies in which one contact partner is replaced by an optically transparent material influence the processes in the contact area. Researchers are therefore forced to examine the surfaces of the contact partners after the actual contact has taken place. Various measuring systems, such as microscopes or laser sensors for surface structure measurement, are used to measure the surfaces of the brake pads. Due to shorter measuring times, mainly only smaller samples from measurements using pin-on-disc tribometers are examined for this purpose. However, various studies show that the friction and wear values of pin-on-disc tribometers cannot be transferred to real brake systems. For this reason
Rosenthal, Tobias Richard, Wiest, Daniel Christian, Meyer, Henning Jürgen
Data to Decisions: An AI-Driven Test Intelligence Platform for Integrated Analysis of Raw Data, Test Reports, and Specification Compliance in Brake System Validation2026-01-0807To be published on 09/14/2026
Validation of brake systems is increasing in complexity due to electrification, software-defined architecture, integrated control modules, and higher functional safety requirements. Although physical testing remains the primary source of engineering evidence, interpretation of results including DVP&R/PVP&R compliance verification, anomaly detection, documentation, and milestone decision support continues to rely heavily on manual engineering analysis. This results in extended feedback cycles, inconsistent interpretation across teams, and limited traceability between raw data, reports, and governing specifications. To support engineers with more objective validation processes, there is a growing need for structured, data-driven intelligence that transforms dispersed test artifacts into actionable engineering decisions. This paper presents Data to Decisions, an AI-driven Test Intelligence Platform designed for integrated analysis of raw measurement data, test reports, validation plans
Divakaruni, Saikiran, Willey, Joseph, Srivastava, Namrata, Sankar, Arya, Namala, Divya, Gowtham, Rahul Sangani
Advanced Brake Force Distribution on trailers with Bendix Electronic Brake Controller2026-01-0797To be published on 09/14/2026
Commercial vehicle fleets frequently operate with tractors that connect to different trailers and dollies, resulting in combinations with varying brake pad wear across wheel‑ends. Traditional brake force distribution strategies whether proportioned, electronic, or load‑adaptive do not account for these pad life differences. This can lead to uneven brake utilization, irregular maintenance intervals, and increased total cost of ownership (TCO), especially in mixed‑fleet and multi‑trailer operations. This work introduces an advanced brake force distribution function, a mechatronic brake control concept that incorporates brake pad health information into supervisory brake force allocation. In the proposed architecture, the tractor is equipped with a Brake Control ECU, which collects brake pad life status from each trailer or dolly through Pad Wear Sensing ECUs over the Tractor‑Trailer CAN (TT‑CAN) network. The Pad Wear Sensing ECUs report pad wear information only and do not host braking
Ganesha, Vinodkumar
Further Investigation of Brake Squeal: Effect of (Inboard/Outboard) Pads Property Differential2026-01-0799To be published on 09/14/2026
It was reported earlier that the wear differential between the inboard pad and the outboard pad leads to brake squeal generation. The (I/O) pads wear differential can occur due to hardware issues such as brake pad drag and/or two different wear rates of the (I/O) pads, which is caused by two different properties of the pads although the pad formula may be the same. The current investigation focuses on the pad property issues. It is found that pad compressibility differential and pad hardness differential are closely related to brake squeal generation. The property differentials are caused by pad porosity variations. The implications of hardness differential on friction/vibration will be discussed.
Liu, Richard, Wu, Shane, Wu, Godot, Li, Aihong, Zou, Tianlang
Correlation of tribological characteristics with Brake Emission Factors in automotive disc brakes2026-01-0829To be published on 09/14/2026
Following the recent introduction of the Euro 7 regulations, research on non-exhaust emissions, including brake wear particles, has increased. However, full-scale dynamometer tests are affected by complex variables such as vehicle class and brake system specifications, which makes it difficult to analyze the unique characteristics of friction materials independently. Previous studies have predominantly focused on comparing emission levels by friction material composition or on disc surface treatments, and quantitative correlations, resolved by friction material type, between the physical wear mass of friction materials and the Brake Emission Factor (BEF), remain scarce. In this study, the brake emissions from various friction materials were precisely measured using a scale dynamometer reflecting the UN-GTR No. 24 standards. By applying the WLTP cycle, a quantitative correlation was derived between the friction characteristics and the BEF for each braking section. The results show that
Jang, Pan Gyu, Kim, Duck Hyeon, Jeong, Yoon Oh, Kwon, Sung-Wook, Jung, Kwang Ki, Lee, Jungju
Time-Series Friction Torque Prediction for Drum Brake Systems via Mixed-Effects Random Forest Framework2026-01-0809To be published on 09/14/2026
The application of drum brake systems is expanding due to increasing cost competitiveness requirements in EV and purpose-built vehicle markets, as well as the introduction of EURO-7 particulate emission regulations. In spite of this trend, drum brake friction behavior is not yet fully understood because it is governed by complex and strongly coupled complicating mechanisms, including temperature history, braking conditions, and interactions between drum brake components. To address this gap, this study presents a method for developing a time-series friction torque prediction model using the Mixed-effects Random Forest (MERF) machine learning framework. Time-series data collected from sensors during drum brake dynamometer tests were analyzed to identify the key variables that govern the friction torque. Significant inputs were selected through Exploratory Data Analysis (EDA), considering test-to-test variability and potential mixed effects, and were then used to train and tune the MERF
Yoon, Jungro, Cho, Sunghyun, Kim, Wonjoon
Influence of Caliper Piston Wall Thickness and Hard Anodizing on Thermal Transfer and Seal Rollback Stability in Hydraulic Disc Brakes2026-01-0822To be published on 09/14/2026
Thermal stability and sealing reliability are critical performance parameters in hydraulic disc brake systems, especially under high-energy braking conditions where elevated temperatures directly influence brake fluid behavior and elastomer seal durability. Lightweight design trends increasingly encourage reduction in caliper piston wall thickness to optimize mass and response characteristics; however, such modifications alter the thermal conduction path and transient heat distribution within the piston–seal interface. This study investigates the combined effect of 50% reduction in aluminum caliper piston wall thickness and increase in hard anodizing thickness from 20 µm to 50 µm on heat transfer characteristics and piston seal rollback consistency. A comparative analytical and experimental approach is adopted to evaluate thermal resistance changes due to variation in anodic oxide layer thickness and piston geometry. One-dimensional thermal modeling is correlated with controlled
Badade, Ashish Laxman
Cast-In Brake Disc – An affordable lightweight design for passenger car brake discs2026-01-0821To be published on 09/14/2026
To meet evolving automotive demands, Fritz Winter is developing new lightweight brake discs. While alternatives to traditional cast iron discs exist, aluminum compound versions are too costly, and mechanically joined steel hat discs present complex assembly and tolerancing challenges. Fritz Winter’s engineering objective was to create a reliable method for joining a steel hat with a cast iron friction ring directly during the production process. This composite design significantly reduces vehicle weight, without compromising durability, comfort, or NVH performance. The methodology involves inserting a finished, stamped steel hat (2.5 to 3 mm thick) into the casting mold and then casting the friction ring directly onto it. This process eliminates the need for subsequent machining of the hat. During development, several key challenges were overcome. A patent-pending sealing process was created to prevent liquid iron from spilling onto the steel hat. To ensure a strong bond and prevent
von Reth, Thomas
Study on the Friction Characteristics of Disc Brakes with Ceramic Surfaces for High Performance Vehicle2026-01-0827To be published on 09/14/2026
In this study, various methods were reviewed to simultaneously satisfy the high-temperature braking performance required for high-performance vehicles and the brake dust criteria by environmental regulations. Among them, the characteristics of two types of Brake disc with ceramic composite surfaces were evaluated to prevent disc wear even under the condition of using metallic friction materials with excellent fade performance. As a result of the evaluation, carbon ceramic disc without metal-to-metal contact during braking showed superior characteristics compared to hard metal cladding disc.
Kim, Yoon Cheol, yeongwoo, cho, KIM, YOUNGMIN
Precise Simulation and Test Closed-Loop Verification of Drag Torque for Brake Caliper of In-Wheel Electric Motor2026-01-0813To be published on 09/14/2026
Aiming at the industrial pain points of high control difficulty of drag torque, low precision of traditional simulation and lack of authoritative test closed-loop verification for the special brake caliper of in-wheel electric motor, taking the YF3501S73 front brake caliper and YF3502S73 rear brake caliper as the research objects, a high-precision finite element simulation method coupling the nonlinearity of piston seal material with bilateral parallel return springs was proposed, and the simulation boundary conditions were calibrated by finely matching the bench test working conditions. To ensure the authority and engineering practicability of the research results, the drag torque bench test was carried out in strict accordance with QC/T 592-2013 Performance Requirements and Bench Test Methods for Hydraulic Brake Caliper Assemblies, and in alignment with the international brake drag test specifications of SAE J2923 and JASO C448, thus realizing a complete closed loop of simulation
Liu, Yuqi
Finite Element–Based Wear Analysis of Brake Pads2026-01-0817To be published on 09/14/2026
Brake pads are essential components that play a critical role in ensuring vehicle safety and braking performance. Variations in the pad–disc contact interface directly affect the behavior of both the disc and the piston, which can lead to reduced braking efficiency, unstable pedal response, or overall brake system degradation. As wear on the pad surface gradually alters the contact conditions, accurately predicting the evolution of brake pad wear is vital not only for maintaining brake stability but also for assessing long-term component durability. In particular wear behavior observed during the burnish evaluation mode is significant, as this phase governs the stabilization of the pad surface and influences the establishment of a steady friction coefficient. In this study, a finite element–based wear analysis procedure was developed using the Archard wear theory to evaluate the wear behavior of automotive brake pads. A wear direction algorithm and an element distortion control
SONG, SEONG IL, JOO, SANG DON, KIM, MIN SOCK, KERSZBERG, NICOLAS, Lee, Heewook
Physics-Informed Machine Learning Digital Twin of Electro-Mechanical Brakes for Clamp-Force and Friction Estimation2026-01-0806To be published on 09/14/2026
As the industry is rapidly moving towards dry-by-wire architectures, accurate Electro-Mechanical Brake (EMB) models are increasingly critical for safety-relevant force control, diagnostics, and consistent performance over temperature and lining wear. However, widely used EMB identification methods often rely on linearized models or 'characteristic curve' calibrations that struggle to generalize across operating regions where friction, hysteresis, and compliance are strongly non-linear and temperature sensitive. Prior EMB force-estimation literatures addressed pad contact detection, hysteresis and thermal compensated clamp-force estimation, yet practical accuracy gaps remain during transients and under changing friction signatures. This work proposes a digital twin based on Physics-Informed Neural Networks (PINNs) that preserves the EMB's governing dynamics while learning both (i) physically meaningful parameters- such as effective system inertia, damping, stiffness etc., and (ii) a
Rai, Prakhar, Gadhvi, Tirth
A Study on the Development of Brake Moan for CTBA Vehicles Using Simulation2026-01-0814To be published on 09/14/2026
Not only are customers' expectations for the development of various products, but also the demand for emotional quality improvement of the products is steadily increasing. Brake NVH, which is generated during vehicle braking, has a lot of influence on the emotional aspects of customers. There are several brake NVH such as judder, squeal, and moan. First, judder is phenomena of handle, brake pedal vibration and noise that occur during braking at the high-speed. The quality of judder has been improved a lot by applying judder detection and compensation logic in internal combustion engines and the heat load on the disc is reduced by regenerative braking in electric vehicles. So the judder problem hardly occurs these days. A squeal is a noise generated during braking at a low speed. The squeal is solved by tuning and shape change of a friction material in the high frequency band and by making the robust systems design such as caliper and disc in the low frequency band. Moan noise is low
KIM, SUNGHO, Kim, Jeongkyu, HWANG, JAEKEUN, Kang, Donghoon
Optimizing Brake Pedal Feel and Driver Comfort in Buses with Pneumatic Braking Systems2026-01-0804To be published on 09/14/2026
Abstract:- Brakes are a critical safety component in vehicles, and every parameter of the braking system plays a vital role in vehicle operation. Among these, brake pedal feel and driver confidence are key factors, in addition to achieving the required brake force, deceleration, and stopping distance. These aspects depend on the system-generated torque, available pneumatic pressure, lining material properties, and Electronic Braking System (EBS) parameters. This paper focuses on the factors influencing brake pedal feel while maintaining a balance between driver comfort and confidence during bus operation. Under optimal braking conditions, brake pedal response and brake torque gradient must align with the driver’s deceleration demands. The braking system must respond promptly, completing the application in the shortest possible duration. The brake torque gradient values specified in the EBS file should be neither too low nor too high, and the brake pedal feel must remain consistent
Pujari, Sachin Subhashrao, Karampurwala, Zoeb, RAJ, AMRITESH
Safe State Definition and Verification for Distributed Multi-Controller EMB Architectures2026-01-0800To be published on 09/14/2026
The Electro-Mechanical Brake (EMB) system is an essential technology for safe braking in modern vehicles. However, the adoption of multi-controller architectures has introduced new challenges to conventional Safe State strategies. Traditionally, the Safe State defined in functional safety means "function shutdown," and in accordance with ISO 26262 definition, aims for an "operational mode without risks exceeding reasonable levels." However, in the multi-controller architecture of EMB systems, the Fail-Operational Safe State concept is applied, where the system continues to provide limited functions even in the event of faults. It is essential to verify whether such operational modes actually satisfy the safety requirements of ISO 26262. This paper redefines the Safe State according to failure modes in EMB systems, analyzes system state transitions, and presents a coherence analysis methodology for validating the availability of resources required to provide limited functions in the
KIM, KANG SAN
Predicting Brake Squeal Occurrence Using Machine Learning with Temporal Feature Analysis of Braking-Torque Test Data2026-01-0812To be published on 09/14/2026
The automotive industry's paradigm shift toward autonomous driving and electrification has introduced new competitors threatening market dominance through differentiated value propositions. In this highly competitive landscape, delivering irreplaceable customer value requires providing sustainable and authentic luxury experiences. Quiet driving represents a tangible value that customers genuinely appreciate. Brake squeal—high-frequency noise arising from torque-induced friction behavior during braking—negatively impacts customer satisfaction and must be suppressed. Despite significant advances in brake squeal prediction modeling, the irregular nature of squeal generation mechanisms has prevented development of a generalized predictive model applicable to product development processes. Development and verification remain largely experimental. This limitation constrains early-phase design validation, as brake squeal is highly sensitive to chassis and braking system design. When squeal
Cho, Sunghyun, Yoon, Jungro, Kim, Yoon Cheol, Kim, Jeongkyu, KIM, SUNGHO, baek, SongYi, KIM, Won Joon, CHOI, KYUNG ROK
Aerodynamic Disc Brake Drag: An Elusive Source of Variability2026-01-0802To be published on 09/14/2026
The ever-present drive to increase vehicle range and efficiency has resulted in disc brake caliper requirements at or near zero residual drag. It is increasingly critical to understand and design around potential edge cases that can drastically increase off-brake drag. One frequently observed, but often misunderstood, phenomenon is drag induced by aerodynamic forces surrounding the brake pad. Complex airflow characteristics surrounding the pad in the brake corner environment can lead to Venturi Effect induced air pressure differentials on each side of the pad, leading to transient, yet pronounced, increases in brake drag. This paper will follow a case study during which brake pad pressure differentials were discovered and experimentally measured, review the Venturi Effect as it relates to brake corners, and explore modelling approaches for identifying and correcting designs that are prone to this phenomenon.
Robere, Matthew, Tresmondi, Thales
Influence of Ferritic Nitrocarburizing with Smart-ONC® on the Modal and Damping Behavior of Gray Cast Iron Brake Rotors2026-01-0798To be published on 09/14/2026
Ferritic nitrocarburizing (FNC) with Smart-ONC® post-oxidation has been developed as a production-capable surface engineering solution for gray cast iron (GCI) brake rotors to meet the Euro 7 non-exhaust particulate emission limits. While prior investigations have demonstrated significant PM₁₀ reduction, improved corrosion resistance, and stable braking performance, the influence of FNC on noise, vibration, and harshness (NVH) performance requires systematic evaluation. This study quantified the relative contributions of the alloy composition, rotor geometry, and FNC treatment to the modal frequency and damping behavior. Seven ventilated disc types from multiple foundries were characterized to assess the composition-driven variability. In addition, 120 production discs (ventilated and solid) were measured before and after FNC processing to isolate the treatment effects. Modal properties were obtained using impulse-hammer testing under free-free boundary conditions in accordance with
Awe, Samuel Ayowole, Holly, Mike, Winter, Karl-Michael
Electro-Hydraulic Brake-by-Wire and Off-the-Shelf ABS Integration: Control Design and Hardware in the Loop Validation2026-01-0795To be published on 09/14/2026
This work presents the design of a control logic for an electro-hydraulic brake-by-wire in series with an off-the-shelf ABS unit for motorsport applications. Validation is performed through hardware-in-the-loop testing with a complete hydraulic layout, including the brake-by-wire actuator, the ABS module, and brake calipers. State-of-the-art electro-hydraulic brake-by-wire systems are increasingly adopted in top-level motorsport and are now transitioning to high-performance road vehicles, in combination with ABS and ESC. However, due to motorsport regulations, racing brake-by-wire systems do not incorporate ABS functionality. To combine the performance of motorsport grade actuators with the ease of use required for non professional drivers, a series configuration between brake-by-wire and ABS represents a natural solution. This architecture is also relevant for future road vehicle applications, offering additional redundancy for autonomous driving-ready systems. A dedicated hardware-in
Milivinti, Massimiliano, Gimondi, Alex, Gobbi, Massimiliano, Cantoni, Carlo
Real-time Estimation of Brake Temperature using Physics-Informed Machine Learning Model2026-01-0810To be published on 09/14/2026
The current work presents a novel approach to estimate brake surface temperature in real time to aid in brake wear prognostics. Brake prognostics involve estimating the brake pad wear in real-time that helps in its predictive maintenance. Brakes are a safety critical system for vehicles, therefore, demands accurate and robust pad wear estimation, ensuring vehicle safety. However, it involves several challenges. The estimation of pad wear is fundamentally a two-stage process: the first stage involves the accurate prediction of brake pad surface temperature, while the second stage utilizes this thermal history to calculate cumulative material wear. A significant challenge in estimating brake pad wear without expensive sensor is that it is sensitive to the surface temperature prediction; any error in the thermal model propagates and compounds in the wear prediction stage. To identify surface temperature, traditional physical sensors are often cost-prohibitive or prone to failure in the
Gannavarapu, Shivadath, Pal, Anuj, Fan, Mengdi
A Study on TSC(Technical Safety Concept) design and verification in EMB(Brake By Wire) Systems2026-01-0801To be published on 09/14/2026
The Electro-Mechanical Brake (EMB) system, a dry-type Brake-by-Wire technology, eliminates hydraulic components by directly controlling friction braking through electrical actuators at each wheel. The architecture includes a Main Center Control Unit, a Backup Center Control Unit for redundancy, and four-Wheel Control Units, communicating via CAN FD. Compliance with ISO 26262 functional safety standards is critical due to the EMB system’s role in vehicle braking. As complexity increases, risks such as hardware failures and communication faults must be systematically addressed. This paper presents the design and verification of a Technical Safety Concept (TSC) for EMB systems in accordance with ISO 26262. Safety goals and Functional Safety Requirements derived from HARA analysis guide the System Architecture and TSC development. Key design principles include modularity, redundancy, fault detection, and fail-safe mechanisms. Verification is performed at both system and vehicle levels
KIM, Dokun
A Multi Body Dynamic Analysis of Click Noise Generated in Rear Brake Caliper2026-01-0815To be published on 09/14/2026
As customer awareness of brake-related NVH(Noise, Vibration and Harshness) continues to increase across the automotive industry, noise originating from braking systems is increasingly regarded as important indicator of vehicle quality. Among these issues, intermittent click noise from rear brake caliper is commonly noticed during low-speed driving and initial brake application and is frequently associated with customer dissatisfaction. In the automotive industry, this noise has primarily been addressed through empirical design modifications and component-level testing. However, due to its low reproducibility and impulsive response characteristics, making quantitative prediction and root-cause identification during the design phase difficult. While most previous brake NVH research has mainly focused on continuous vibration phenomena such as squeal and groan, fewer studies have examined single-event impact noise related to pad-to-carrier clearances, contact transitions, and frictional
Choi, Hyeontae, Kim, Sangbum, Park, Ilho, Kim, Taeuk, Kwon, Yongsik, Yang, Soonhong, Ma, Jaehyeon, Kim, Jinwook
A Virtual Methodology to Define Air Tightness Criterion for Brake Calipers Based on Experimental Data2026-01-0818To be published on 09/14/2026
Air tightness in brake calipers is a critical requirement for ensuring braking system reliability and safety. However, defining a clear and practical analytical criterion for air leakage prediction remains challenging due to the complex contact behavior at the seal–piston interface. This study presents a virtual methodology to define an air tightness criterion for brake calipers based on experimental evaluation and structural analysis. The seal squeeze ratio was selected as the primary design variable to evaluate its effect on sealing performance. Test samples with different seal squeeze ratios were manufactured, and air tightness was tested under controlled pneumatic pressure to determine when leakage occurred. In parallel, a finite element (FE) structural analysis was conducted to simulate the seal installation process and quantify the resultant contact pressure distribution between the seal and the piston surface. To support reliable structural analysis, preliminary experiments were
Cho, Inyong, Kim, Beomseok
Modeling Brake Torque Hysteresis for Chassis Controls Hardware In the Loop Simulation2026-01-0824To be published on 09/14/2026
It is hardly a new trend for on road, vehicle intensive tuning and testing of chassis control features such as Anti-Lock Brakes, Traction Control, and Electronic Stability Control to move away from vehicle testing and towards non-vehicle test platforms such as Hardware-In the Loop (HIL) simulations and even further into pure math-based simulations. However, a significant acceleration of these activities has been occurring recently in the automotive industry, reducing or eliminating calibration time on vehicles and amplifying the demand for highly representative, non-vehicle test platforms to calibrate and even to validate chassis controls features. In current state of the air HIL simulation, the input (brake pressure) to output (brake torque) of each wheel brake in a vehicle’s brake system is modeled relatively simplistically, including at most pressure and brake temperature sensitivities, usually in lookup table form. Each brake corner contains over 20 different friction interfaces
Antanaitis, David, Ridenour, Nick, Miller, Bryan, Karnjate, Timothy
The Biomechanics of Brake Pedal Feel2026-01-0796To be published on 09/14/2026
Brake pedal feel is arguably the most important driver-facing characteristic of a vehicle’s brake system, as it represents the main interaction between the brake system and the driver and is experienced by the driver in every trip taken. It has traditionally been characterized by three fundamental curves - deceleration versus force at the pedal pad, deceleration versus travel at the pedal pad, and travel at the pedal pad versus force (which is derivable from the other two curves). These characterizations, while useful, stop short of describing what the driver actually experiences - felt through the force in and contraction of his or her leg muscles. When brake pedal feel is traced away from the brake pedal pad and into the driver’s leg, a complex new system emerges, containing the brake system and the biomechanics of the driver. This expanded system is now subjected to - but can also help explain - influences such as seating position, foot position, brake pedal geometry, and the
Antanaitis, David, Antanaitis, Rebecca, Morris, Brock
Influence of Modified Fly Ash Content on the Properties of Resin-Based Friction Materials2026-99-1657To be published on 07/24/2026
In this study, five resin-based brake pad samples with modified fly ash contents of 0%, 4%, 8%, 12%, and 16% were prepared to investigate the influence of fly ash content on the comprehensive performance of the friction materials. The tribological properties of all samples were evaluated under temperature conditions ranging from 100 °C to 350 °C, and their overall performance was assessed using five evaluation indices. Based on the AHP-MOORA algorithm, sample F12 exhibited the highest comprehensive weighted score of 0.11, followed by samples F0 and F8 with scores of 0.10 and 0.09, respectively, indicating a slight decline. In contrast, the comprehensive weighted scores of F4 and F16 were relatively low, at 0.05 and −0.01, respectively. Among the five composites, F12 demonstrated the best overall performance, with F0 and F8 ranking next, while F4 and F16 performed poorly. These results suggest that, within a certain range, increasing the fly ash content can enhance the comprehensive
Li, Xiaobiao, He, Kang, Zhao, Zhuanzhe, Wu, Bo, Sun, Fei
Design and Analysis of Orthogonal Excitation Eddy Current Brake for High-Speed Trains2026-99-05137/10/2026
As high-speed train technology advances, the demands on braking system performance have intensified. Known for their efficiency, reliability, and eco-friendliness, Linear Eddy Current Brakes (LECB) have become a focal point in the research and development of high-speed train braking systems. This paper presents an innovative Orthogonal Excitation Eddy Current Brake (OEECB), which enhances the braking force without modifying the overall dimensions of the conventional LECB. By adding a set of longitudinal excitation coils parallel to the rail surface, the OEECB creates an orthogonal excitation structure that augments the braking force. Initially, this paper outlines the design concept of the OEECB and then analyzes its working principle based on electromagnetic field theory. Subsequently, a finite element solver is employed to numerically model the electromagnetic characteristics of the OEECB. Finally, by comparing the performance differences between the conventional LECB and OEECB, the
Huang, Liuwen, Zuo, Jianyong, Zhang, Yu
A Transition Curve-Based Design Method for the Recirculation Channel in Internal Recirculating Ball Screws15-19-03-00117/1/2026
Internal recirculating ball screws are widely used as linear motion components in automotive active safety systems, owing to their simple structure and compact size. The recirculation (or deflection) channel is a key feature that distinguishes this type from other ball screw designs. The objective of this article is to investigate this key feature that has been rarely addressed in existing research on internal ball screw. The conventional design method for the recirculation channel involves sweeping the cross-section along the center curve. The center curve is typically defined by various classical equations. These equations are applied in different application scenarios. In automotive braking systems, high loads and strict size constraints place critical demands on both the recirculation channel and its center curve. As a representative best-practice example, the machined channel in the screw is typically employed in this application. This article compares several classical center
Xia, Xinan, Xia, Yanzhe, Zhao, Tina
Impact of Network-Induced Delays on Autonomous Vehicle Steering Stability10-10-03-00246/25/2026
This article presents a cross-layer framework that integrates realistic vehicle-to-network-to-vehicle (V2N2V) delay characterization with a rigorous stability analysis of automated vehicle steering control. Both constant and network-induced time-varying delays modeled via deterministic bounds are addressed. For constant delays, delay-independent stability regions within the controller gain space are analytically derived. For time-varying delays with stochastic network origins, modeled using deterministic bounds, a refined Lyapunov–Krasovskii functional (LKF) incorporating augmented single- and double-integral terms is constructed. To establish delay-dependent linear matrix inequality (LMI) conditions, a reciprocally convex combination approach is employed to handle the delay interval partitioning, and the second-order Bessel–Legendre inequality is applied to tighten the integral quadratic bounds. The resulting LMI conditions explicitly capture the coupled effects of delay magnitude
Li, Jialin, Lu, Jianwei, Wei, Heng, Ao, Di
Reduced Effort Brakes and Reduced Effort Vacuum Powered Brake Backup SystemsJ2671_202606 (Current)6/22/2026
This Information Report relates to a special class of automotive adaptive equipment which consists of modifications to the power brake booster systems provided as original equipment of motor vehicles. These modifications are generically called "Reduced Effort Power Brakes" (REPB) The purpose of the modification is to lower the amount of driver effort required to apply the brakes. Retention of reliability, ease of use and maintainability for disabled drivers, passengers, and the general public is of primary concern. Reduced Effort Power Brake modifications should be qualified by the tests referenced in the Recommended Test Procedure. The tests set forth in that procedure should be applied, and failure of a Reduced Effort Power Brake modification to meet those tests should disqualify the modification from the claim of meeting the specifications of this Information Report. Because this is an Information Report, the numerical values for performance measurements presented in this report and
Adaptive Devices Standards Committee
Design-Driven Sustainability of Automotive Components: A Comparative LCA from Conventional to Metal and Composite Additive Manufacturing2026-37-00376/9/2026
The increasing pressure to decarbonize manufacturing systems is pushing industry beyond conventional lightweighting strategies toward material and process paradigms, capable of delivering functional performance with radically lower environmental impact. In this context, polymer-based composite Additive Manufacturing (AM) offers an underexplored yet highly promising pathway for sustainable production of load-bearing components. This study presents a preliminary comparative cradle-to-gate Life Cycle Assessment (LCA) of a Formula SAE brake pedal, assessing the environmental transition from conventional sheet metal fabrication and finishing operations of Aluminum 7075-T6 to additive manufacturing solutions, with specific focus on Carbon-Fiber-Reinforced Polymer (CFRP) composites. Two topology-optimized designs, respectively for Powder Bed Fusion (PBF) in AlSi10Mg and Material Extrusion (MEX) in Polyethylene Terephthalate Glycol with Carbon Fiber (PETG-CF) are compared to conventional
Dalpadulo, Enrico, Russo, Mario, Apté MD, Raphaëlle, Leali, Francesco
On Natural Gas Combustion Split into Diesel Like Architecture of a Compression Ignition Engine Retrofitted for Spark Ignition Operation2026-37-00296/9/2026
In commercial areas that no longer favor diesel engines, such as Europe, it might be interesting to convert an existing compression ignition engine to the spark ignition operation and to use natural gas (NG) because of its advantages: availability of still abundant supplies worldwide and environmental benefits compared to conventional liquid fossil fuels. This paper first presents experimental results on NG combustion inside such a converted engine with diesel-like architecture dedicated to light-duty vehicles and passenger cars. Particularly, our study carried out at the engine test bed revealed that in certain operating points (low speed and load, stoichiometric mixture and rather high spark advance), the combustion is split into two distinct events (first, a fast combustion inside the cylinder and piston bowl and then, a slower combustion occurring outside the bowl-in combustion chamber, in other words, in the squish region), which is not specific to the standard spark ignition
Clenci, Adrian F., Popa, Robert, Berquez, Julien, Iorga-Siman, Victor, Magheru, Catalin, Punov, Plamen, Niculescu, Rodica
Coordinated Path Tracking and Stability Strategy for Distributed Drive Electric Vehicles Using Model Predictive Control with Dual Feedback Adjustment10-10-04-00346/3/2026
Distributed drive electric vehicles (DDEVs) provide enhanced maneuverability through independent wheel torque control, but coordinating precise path tracking with lateral stability remains challenging under aggressive driving conditions. This paper presents a coordinated control strategy that integrates model predictive control (MPC) for path tracking with a proportional gain controller for stability regulation. The proposed framework adopts a hierarchical design. The path tracking control leverages MPC to compute front steering commands while accounting for vehicle dynamics and preview errors. The stability adjustment uses dual proportional gain controllers to generate an additional yaw moment, which is adaptively balanced through a phase plane coordination mechanism, enhancing yaw stability during path tracking. The generated yaw moment is subsequently distributed to individual in-wheel motors with an optimization torque allocation method, respecting tire force limitations. The
He, Yang, Zhu, Yuzheng, Guo, Ruixin, Zhu, Yueying, Xing, Chao, Liu, Shuangxi, Lin, Yier
Driveline Parking Brake Test Procedure for Medium Duty VehiclesJ2690_202606 (Current)6/3/2026
This SAE Recommended Practice establishes uniform test procedures for friction based parking brake components used in conjunction with hydraulic service braked vehicles with a gross vehicle weight rating greater than 4500 kg (10 000 lb). The components covered in this document are the primary actuation and the foundation park brake. Various peripheral devices such as application dashboard switches or indicators are not included. These test procedures include the following: a Brake Related Tests 1 Brake Functional Performance 2 Brake Dynamic Torque Performance 3 Brake Corrosion Resistance 4 Brake Endurance with Torque 5 Brake Endurance without Torque 6 Vibration Resistance 7 Brake Ultimate Static Load 8 Brake Lining Wear Adjuster Function b Actuation Related Tests 1 Mechanical Actuator Functional Performance 2 Mechanical Actuator Endurance 3 Mechanical Actuator Quick Release 4 Mechanical Actuator Ultimate Load 5 Spring Apply Actuator Functional Performance 6 Spring Apply Actuator
Truck and Bus Hydraulic Brake Committee
Heavy-Duty Nonroad Material Handler Electrification Part 2: Energy Efficiency and Performance Evaluation02-19-03-00166/2/2026
Decarbonization efforts achieved through electrification in nonroad mobile machinery can realize a reduction in fuel consumption of more than 20%, thanks to concepts familiar to light-duty passenger vehicles. This case study compares the results of a hybrid-electric material handler to its conventional counterpart, utilizing machine-specific drive cycles presented in part one of this paper series. The hybrid prototype features an extended-range electric vehicle (EREV) powertrain that demonstrated substantial energy efficiency improvements. Specifically, there was a reduction in equivalent fuel consumption of 75% when operating in electric-only mode, and 33% when maintaining the battery by charging with an on-board generator. Together, the efficiency improvements can be extrapolated over a low-intensity, 8-h shift characterized by significant idle time and highly dynamic engine load for a 47% reduction in net energy consumption. Key technologies that led to this improvement included
Czarnecki, Alexander, Goodenough, Bryant, Worm, Jeremy, Robinette, Darrell, LaTendresse, Phil, Westman, John, Subert, David, Heath, Matthew, Kiefer, Dylan, Black, Andrew
Limit Stability Control for Corner Module Vehicles Based on Hierarchical Hybrid Game10-10-04-00325/18/2026
Corner module vehicles (CMVs) achieve the decoupling of driving, braking, steering, and suspension, significantly enhancing vehicle handling potential, but under extreme operating conditions, the interactions between actuators severely constrain the improvement of vehicle handling performance. In order to mitigate conflicts between subsystems and enhance vehicle handling stability, a hierarchical hybrid game–based limit stability control method for CMVs is proposed in this article. Taking into account the handling potential of subsystems under limit conditions, a Stackelberg leader–follower game is designed by first designating Direct Yaw moment Control (DYC) as the leader and Active Rear Steering (ARS) as the follower. Subsequently, the DYC–ARS and Active Suspension System (ASS) were constructed into a non-cooperative game system, and the Nash equilibrium solution was solved through iteration. The lower-level controllers, respectively, established a tire force distribution model that
Peng, Jinxin, Xiao, Feng, Ke, Yuan, Jin, Liqiang
Coordinated Stability Control for Active Rear Steering Vehicles Based on Dynamic Stability Region2026-99-07135/15/2026
To improve the handling stability of four-wheel steering/drive vehicles under complex high-speed maneuvers, this study proposes a coordinated control strategy that incorporates Active Rear Steering (ARS) and Direct Yaw Moment Control (DYC) based on a dynamic stability region. Firstly, a four-wheel steering vehicle dynamics model including lateral motion and yaw motion is established, and the ideal values of the control variables are determined. Secondly, combined with the fuzzy control theory and double-line method, the boundary of the dynamic stability region is obtained in the sideslip angle-sideslip angle rate β−β̇ phase plane, and the vehicle state is categorized into stable, unstable, and critical stable region. Then, A hierarchical control architecture is designed based on the stability boundary. The upper controller comprehensively solves the target rear wheel angle and additional yaw moment through feedforward feedback control; the coordinated control layer allocates control
Nie, Kehe, Chen, Jin, Wang, Falong, Li, Ren, Bai, Xianxu
Reinforcement Learning-Based Controller for Tiltrotor Aeroelastic Stability Augmentation (Presentation Only)F-0082-2026-03365/5/2026
This study investigated the feasibility of using Deep Reinforcement Learning (DRL) for aeroelastic stability control of a Tiltrotor Aeroelastic Stability Testbed (TRAST) model. The DRL controllers use rotor swashplate inputs to minimize oscillatory wing root bending moments of the tilt rotor model. First, three DRL-based agents including Deep Deterministic Policy Gradient (DDPG), Twin Delayed Deep Deterministic Policy Gradient (TD3), and Soft Actor-Critic (SAC) were investigated to control the aeroelastic stability of the TRAST model throughout a wide range of airspeed including where the whirl flutter occurs. All three agents demonstrated the capability of stability augmentation while the SAC agent demon-strated the most robust performance. Next, the effectiveness of the SAC agent was studied further by training the SAC agent at a certain airspeed and applying the trained agent through the TRAST whirl flutter conditions. Finally, additional tuning of the SAC agent was performed to
Husain, Syed, Floros, Matt, Anusonti-Inthra, Phuriwat, Kang, Hao
The Effect of Initial Foot Position on THOR-50M and THOR-05F Lower Leg Response in a Realistic Vehicle Buck09-14-01-00085/4/2026
This study aims to explore and evaluate the effect of various foot positions on the kinematic and kinetic response of the lower extremity during frontal crashes using a realistic vehicle interior. Frontal impact sled tests were performed with the Test Device for Human Occupant Restraint, 50th-percentile Male (THOR-50M) and Test Device for Human Occupant Restraint, 5th-percentile Female (THOR-05F) anthropometric test device (ATD) in the driver’s seat of a midsize SUV testing buck (with realistic interior components including an instrument panel with steering wheel and steering wheel airbag, seat, three-point seat belt with pretensioner and force-limiter, accelerator pedal, brake pedal, knee airbag, and seat belt retractor pretensioner). Six sled tests were performed in two principal directions of force (PDOF) [three each in frontal (0°) and oblique (−20°) configurations]. The right foot was positioned on the accelerator pedal, fully on the brake, and half on the brake. A single test was
Noss, Junior, Donlon, John-Paul, Morris, Anna, Samier, Germain, Park, Joseph, Forman, Jason
Braking Performance - Rubber-Tired, Self-Propelled CranesJ1977_202604 (Current)4/25/2026
This SAE Standard applies to machines as defined in Appendix A. Some of these machines can travel on-highway but function primarily off-highway.
Cranes and Lifting Devices Committee
Embedded Real-Time Control of a Distributed Trailer Propulsion System with Regenerative Braking for Net Neutral Load Towing2026-01-00654/7/2026
Towing imposes substantial efficiency penalties on both battery-electric vehicles (BEVs) and internal combustion engine (ICE) vehicles, reducing range by 30-50%. This paper presents a proof-of-concept embedded control architecture for distributed trailer propulsion that actively regulates drawbar force to reduce towing loads. Unlike proprietary e-trailer systems requiring specialized hardware, the proposed implementation demonstrates feasibility using commercial off-the-shelf (COTS) components and open-source software. The distributed architecture employs dual Raspberry Pi 4B single-board computers communicating via ROS 2 at 20 Hz. The trailer-mounted controller executes a Simulink-generated control node coordinating load cell acquisition (HX711 ADC), motor CAN bus telemetry, and throttle commands to a 5 kW BLDC traction motor powered by a 5 kWh LiFePO4 battery pack. A vehicle-mounted controller logs OBD-II/CAN validation data. The control pipeline implements cascaded EWMA/Hampel
Joshi, Gaurav, Adelman, Ian, Liu, Jun, Donnaway, Ruthie
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